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Topic: Cat Engine Air Filter Dilemma (Read 1928 times)

My 2005 motorhome is built on a Freightliner XC chassis, with a Cat C7 350HP engine. I’ve owned it for 12 years now.

I have my spent engine oil analyzed every year when I change it. Three times in 12 years, Blackstone Lab has reported a higher than normal level of silicon in my oil. For example, this year my silicon level was 19ppm, when it should have been at 10 or below. Blackstone states that this is an indication of dirt getting past the engine air filter. Each time this has happened, it was near the end of service life for that particular air filter, which is two years. I have checked my air intake system for any signs of a leak, but I could not find anything. I am left guessing that my paper element air filters must not holding up. I considered a K&N air filter, but K&N’s website doesn’t show a filter for my engine, part no. 0594-HH2. The only other thing I can think of doing is to replace the stock air filter every year instead of every two.

Assume you have checked for other "routes" for dirt to enter the engine. Seal at top of oil dip stick tube and seal at the bottom of the tube should be checked.

Also make sure you are using the correct filter element. Two filters can look VERY similar (size and shape exactly the same), but very different in design. Some are designed for air flow from outside to inside, others inside to outside and yet others are bidirectional.

Neither design (air flow direction) is better/worse, but you need a filter designed for YOUR direction of air flow.

The danger with a filter of correct dimensions, but incorrect direction of air flow is that the element can collapse and break down as it is "sucked" in a direction where it lacks support.

Thanks for the reply Brett. There are only two air filters listed for my engine, one made by Far and the other by Baldwin. I have a very bad back and the angle of my filter canister makes it difficult for me to personally access, so I pay my mechanic to change it for me every two years. That being said, I can not attest to whether it is installed correctly or not. I checked the air intake system myself, but I will have my mechanic inspect it as well at my next service.

Thanks for the reply Brett. There are only two air filters listed for my engine, one made by Far and the other by Baldwin. I have a very bad back and the angle of my filter canister makes it difficult for me to personally access, so I pay my mechanic to change it for me every two years. That being said, I can not attest to whether it is installed correctly or not. I checked the air intake system myself, but I will have my mechanic inspect it as well at my next service.

I did not think of the oil dipstick seals, thanks for the tip.

Craig

What ever you do don't buy a K&N filter they let more dirt in than Cat allows. I would try changing your filter yearly and see if that helps.Have a Happy New Year.Bill

Unless you drive a LOT of miles or in extremely dusty conditions (dirt roads) you should not need to change the air filter every year-- unless you see high restriction on the air filter minder.

Caveats:

The air intake system does not allow the air filter to get wet. If it does, modify it so the filter is always dry.

Record air filter minder reading after the first trip with a new filter element. This is really important, as it establishes a base line for restriction. If readings with a new filter element are high, find and correct the restriction (opening on side of coach, flex hose to filter, filter size, etc).